GPU acceleration works perfectly fine on my humble $69.90 ATI Radeon 4600 on x64. However all cards have limitations, for example most of them don't allow single objects larger than 128 or 256MB in memory, no matter how many GB of video RAM they have, and for that the program can automatically downscale large images to make them fit within those cards limitations. Did you inadvertently tweak the default settings, causing the program to attempt to load images larger than your card can handle in video memory?

using defaulted settings, behaviour has been identical through all 3 videocards on x64i tried lowering memory below default, still the same thing axel..difference on x86 were significant so would be super if it worked out on my new much improved desktop

The acceleration support depends entirely on Direct3D, which in turn depends entirely on the driver. The program does not know (and care) much about the actual card and tries to be as generic as possible. On Vista and Windows 7 the program use the D3D9Ex DDI.

It is possible that some driver writer did not yet enable all functions on the older and little-used D3D9Ex device driver interface introduced in Vista in their shiny new x64 driver, concentrating on plain old D3D9 (without "Ex") and D3D 10/10.1/11 first for their top cards?

There is a registry setting that you may want to try and which force the program to use the old (XP era) D3D9 interface instead of D3D9Ex:

Add a FallbackToD3D9 REG_DWORD value, and set it to 1 in HKEY_CURRENT_USER\Software\ARSD\FastPictureViewer

Besides that, what happens when you say it fails? Are you getting garbage on screen, or an error message? Did you try to set the auto-recasling to a low value, e.g. 32 or 64MB/image, as a test?

tested registry as suggested and lowered settings, still no go.as in fail there is one second lag scrolling images using gpu, it´s not workablei´ve even reinstalled directx and latest drivers, still no go on the radeonat xp 32bit gpu worked very well with my older nvidia.maybe others could report their experiences using gpu on win7 x64

...well... the program is created on Windows 7 x64 and about 50% of the current 5 digits user base (which is a still 5 digits number...) are on that platform now. The program was running in 64-bit on that OS long before it was called "seven" I'm not aware of any widepread issue but I'll still keep an eye on that.

Axel wrote:...well... the program is created on Windows 7 x64 and about 50% of the current 5 digits user base (which is a still 5 digits number...) are on that platform now. The program was running in 64-bit on that OS long before it was called "seven" I'm not aware of any widepread issue but I'll still keep an eye on that.

I understand that many must be using it fine, but for me the program is MUCH slower on my windows 7 x64 with 8GB ram (Q6600CPU and Nvidia 8800 GTS640MB card) machine when GPU acceleration is on.

It's 2-3 times slower. My video drivers are up to date according to windows update (sorry I don't have exact revision number on hand, but it's been slower since I bought the program several months ago)

On my laptop with Vista32 and an ATI card of some sort, the program is wildly faster with GPU accel turned on.

I've just fixed something that might have a positive effect on the behavior you observed: there is a possibility that the program misinterpreted the amount of available video memory (on some Big cards) and aggresively unloaded images to conserve memory. As a result, the preloading was essentially turned off, which, depending on the images, might cause the delay you reported...

definately on to something axel, although i noticed when increased preload fpv got slower & decreasing faster?will test some more tomorrow, it's late here and need to get some sleep, maybe i'm hallucinatingwell done, so much better, at least herethanks for looking into this

Make sure you set the preloading hint slider to a reasonable value (about 1/3 is a good starting point). The issue had to do with the detection of available video memory (which was wrong on some high-end cards in the 64-bit version) and which affected the program's dynamic resource usage adjustment, causing some images to be unloaded sooner than necessary. In some extreme cases the issue caused the program to disable preloading altogether when GPU acceleration was in effect

Setting the preloading hint slider above about half way may cause the computer to trash (not crash, but crawl helplessly and run far slower then expected) if the images are large and the disks not fast enough. Setting the slider all the way to the right is not recommended, unless you have an very fast computer and extremely fast disks, like an SAS RAID10, or if all your images are relatively small. If your disks are not able to sustain 300MB/s real world random file I/O, stay away from the far right...